The present invention refers to an installation for cutting a workpiece, in particular flat stock, comprising a grate of supporting elements for said workpiece which are capable of being moved out of a supporting position. Such installations are known, e.g. from EP-A-0,464,296, in particular for cutting flat stock by means of a laser beam. In the abovementioned installation, pivotable supporting arms for said flat stock can either be swung away by a small angle in order to avoid the laser beam during its passage over a given supporting arm and thus to prevent damages, or said supporting arms may be swung down completely in order to drop cut pieces or residual skeletons onto a conveyor belt. In this case, an individual driving member, e.g. a pneumatic cylinder, is associated to each supporting arm. This construction is complicated, and the compressed air consumption is considerable. The space requirement of each individual driving unit does not allow to reduce the distance between neighboring supporting arms below a certain limit. It may also be difficult to contain the noise, particularly when all supporting arms are lowered simultaneously.